This invention relates to grommet assemblies and more particularly to a two piece grommet assembly which is installed by the application of opposed axial force to lock the assembly together within a panel skin.
In the aerospace industry it is often desirable to attach various kinds of fasteners to a panel skin. In some instances, particularly when using advanced composite materials, certain kinds of fasteners cannot be directly placed in a hole formed in the material. In the case of composite materials, there is very low bearing strength and a tendency for the material to wear excessively around the perimeter of the hole because of the fibrous nature of the material. Corrosion caused by many standard fastener materials is another problem with the use of composite materials. Only certain metals such as titanium and MP35, a nickel based steel alloy, are compatible with many of the composite materials presently being used. Consequently, isolation between the perimeter of the composite material and the fastener material must be maintained. By using grommets made of selected materials, fasteners made from any material can be effectively used in composite panel skin materials.
Another problem encountered in any panel skin material is deformation of fastener holes due to stresses encountered over prolonged periods. Generally, these holes must be redrilled and oversized fasteners must be installed. It is sometimes not feasible for various reasons to use different size fasteners than the size originally used. Grommets constructed in accordance with the present invention will solve this problem as well.